Anyone using them?

I once used a multipolygon relation for a pond with an island in the middle of it.

Other than that I haven’t had need to use them. I’ll probably look at them a bit more in the future once others have worked out the best places and situations to use them in. They still appear quite immature at the moment. Editor support in josm is quite basic and I believe potlatch doesn’t support them at all.

Some people are learning to use multipolygons for drawing building blocks:

I regularly use relations for cycle routes. (they get rendered on the cycle map)

Of course, when I need them, I also use multipolygons.

I have used:

  • Multipolygon: for lakes with islands.
  • Routes: for bicycle routes. (and planning to do some bus routes soon)
  • Bridge: to be able to put the name of the bridge itself somewhere.

The last one isn’t used for/by anything yet. But if nobody supplies data, then the nice features talked about in that proposal will never materialise.

I’m using dual_carriageway and turn_restriction (when I remember).

Half year ago, I failed to convince OSM to take out segments and use polyline data structure to model polygons. OSM is now using relation to model polygons which is a nightmare to render program. In my opion, relation data structure is good for mapmaker to model the map but it is a bad design for render program because polygon can become supper polygons → very hard to clip and fill.

I’m using dual_carriageway and turn_restriction (when I remember).

If you use relation to capture routing information then it may make things become difficult for routing application to calculate a route.

How about naming archipelagos or just a pair of islands? Wouldn’t relations be handy in that case?

I have been using relations for precise bus and road routes in Melbourne, Australia during the past few weeks, in conjuction with the ref=number tags (for roads).

Have you had any problems with this? When people split ways or delete them?

Probably a good idea, any specific archipelago you are thinking about?

No problems as of yet, but they are just there for editing/database purposes at the moment as they do not get rendered in the ways I use them. Also, where I edit, there is low editing activity so I haven’t had any issues as of yet. I just wish they would merge the mailing lists with the forum so communication was easier. :sunglasses:

I was mapping some lakes where a couple of islands had names such as “Sillebrånsöarna”, i.e. they were not labelled individually but as a pair. This made me interested in how names of archipelagos are represented but I couldn’t find anywhere such naming occurred.

Yeah I had the same problem when I was naming a pair of lakes called “Dellen” or “Dellen lakes”, but locally they are called “North Dellen” and “South Dellen”. Have you tried to use relations to do this? I Haven’t just yet, since I didn’t have more than one case to compare with.

This is the map of Dellen lakes. No name labels yet…

I made a relation called “group”, but another name maybe would be suitable. Here’s an example: group: Sillebrånsöarna

Edit: I changed the relation to